Python Datatypes

Python is a popular programming language that is widely used for web development, scientific computing, data analysis, artificial intelligence, and more.

In this blog post, we will provide an overview of the most commonly used datatypes in Python.

Datatypes in python:

There are mainly four types of basic primitive Datatypes,
available in python

Numeric: Int, Float and Complex

Sequence: String, List and Tuple

Sets

Dictionary

Integer datatypes:

Integer datatypes are represent whole integer values and representing using "int()" class,

we can store positive and negative values.

---> Directly assigning an integer value to a variable or using a "int()" class

example: x = 1

y = 3565622255488771

z = -3255522

print(type(x))

print(type(y))

print(type(z))

Float datatype:

Float datatype to represent floating-point value or decimal values, we can use a float datatype,

and it can use an exponential form also called scientific notation.

exanple : x = 1.10

y = 1.0

z = -35.59

print(type(x))

print(type(y))

print(type(z))

complex datatype:

A complex datatype is a complex number is a number with a real and imaginary component

representing as a+bj where a and b are contain integer or float point value

example : x = 3+5j

y = 5j

z = -5j

print(type(x))

print(type(y))

print(type(z))

String datatype:

A string datatype is a sequence of characters enclosed within a single quotes or double quotes or triple single quotes or triple double quotes this character could be anything like letter, number or special character enclosed with quotes.

------> A string is immutable that is it can't be changed once define

------>A string is in orderded we can perform in indexing and slicing

example :

string_1 = 'this a string enclosed in single quotes.'

string_2 = "this a string enclosed in double quotes."

string_3 = '''this is multiple line

string, which has

lines in it enclosed in triple single quotes.'''

string_4 = """this is multiple line

string, which has

lines in it enclosed in triple single quotes."""

String can be indexing:

Positive indexing:

since strings are a sequence of chars, and this seq has an order. We can access individgual chars by their index or position in that seq enclose in [].
x = 'python'
string x has a len of 6, (len of string is equals to the number of chars in that string) the first index is 0 indexing in python starts with 0

example:

a = "Hello, World!"

print(a[1])

Negative indexing:

we can also access the chars in a string using reverse indexing.
reverse indexing starts at the end of the string, reverse indexing starts with -1

example:

a = "Hello, World!"

print(a[-2])

String can be slicing:

as the word suggest, we can get a sub-string of the given string by performing slicing
to slice a string, we need three values: start_index, end_index, step_size
- start_index: from where the slicing has to start, or the starting index of sub-string.
- end_index: in slicing, end index is end index - 1. end_index tells till which index the slicing has to happen, (we are not going to include char at end_index)
- step_size: it talks about how many steps it has to move while performing the slicing. by default, step_size is +1
syntax for slicing:
- var[start_index: end_index: step_size]

example:

` b = "Hello, World"

print(b[2:5])

print(b[2:])

print(b[-5:-2])

String Concatenation:

To concatenate, or combine, two strings you can use the + operator.

example:

a = "Hello" a = "Hello"

b = "World" b = "World"

c = a + b c = a + " " + b

print(c) print(c)

String Methods

center() Returns a centered string

count() Returns the number of times a specified value occurs in a string

split() Splits the string at the specified separator, and returns a list

splitlines() Splits the string at line breaks and returns a list

startswith() Returns true if the string starts with the specified value

strip() Returns a trimmed version of the string

swapcase() Swaps cases, lower case becomes upper case and vice versa

title() Converts the first character of each word to upper case

translate() Returns a translated string

upper() Converts a string into upper case

zfill() F string with a specified number of 0 values at the beginning

capitalize() Converts the first character to upper case

casefold() Converts string into lower case

join() Joins the elements of an iterable to the end of the string

ljust() Returns a left justified version of the string

lower() Converts a string into lower case

lstrip() Returns a left trim version of the string

maketrans() Returns a translation table to be used in translations

partition() Returns a tuple where the string is parted into three parts

replace() Returns a string where a specified value is replaced with a specified value

rjust() Returns a right justified version of the string

rpartition() Returns a tuple where the string is parted into three parts

rsplit() Splits the string at the specified separator, and returns a list

rstrip() Returns a right trim version of the string

List datatypes:

Lists are used to store multiple items in a single variable.

Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage.

example:

thislist = ["apple", "banana", "cherry"]

print(thislist)

List Items

List items are ordered, changeable, and allow duplicate values.

List items are indexed, the first item has index [0], the second item has index [1] etc.

Ordered

When we say that lists are ordered, it means that the items have a defined order, and that order will not change.

Changeable

The list is changeable, meaning that we can change, add, and remove items in a list after it has been created.

Allow Duplicates

Since lists are indexed, lists can have items with the same value

example:

thislist = ["apple", "banana", "cherry", "apple", "cherry"]
print(thislist)

List Length

To determine how many items a list has, use the len() function:

example

thislist = ["apple", "banana", "cherry"]
print(len(thislist))

List Methods

append() Adds an element at the end of the list

clear() Removes all the elements from the list

copy() Returns a copy of the list

count() Returns the number of elements with the specified value

extend() Add the elements of a list (or any iterable), to the end of the current list

index() Returns the index of the first element with the specified value

insert() Adds an element at the specified position

pop() Removes the element at the specified position

remove() Removes the item with the specified value

reverse() Reverses the order of the list

sort() Sorts the list

Python Tuples

Tuples are used to store multiple items in a single variable.

Tuple is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Set, and Dictionary, all with different qualities and usage.

A tuple is a collection which is ordered and (unchangeable)immutable.

Tuples are written with round brackets.

example:

x = ("apple", "banana", "cherry")

print(x)

Ordered

When we say that tuples are ordered, it means that the items have a defined order, and that order will not change.

Unchangeable

Tuples are unchangeable, meaning that we cannot change, add or remove items after the tuple has been created.

Allow Duplicates

Since tuples are indexed, they can have items with the same value

example:

x = ("apple", "banana", "cherry", "apple", "cherry")

print(x)

To create a tuple with only one item, you have to add a comma after the item, otherwise Python will not recognize it as a tuple.

example:

x = ("apple",)

print(type(x))

x = ("apple")

print(type(x)) #NOT a tuple

Python Sets

Sets are used to store multiple items in a single variable.

Set is one of 4 built-in data types in Python used to store collections of data, the other 3 are List, Tuple, and Dictionary, all with different qualities and usage.

A set is a collection which is unordered, unchangeable*, and unindexed.

Set Items

Set items are unordered, unchangeable, and do not allow duplicate values.

Unordered

Unordered means that the items in a set do not have a defined order.

Set items can appear in a different order every time you use them, and cannot be referred to by index or key.

Unchangeable

Set items are unchangeable, meaning that we cannot change the items after the set has been created.

Duplicates Not Allowed

Sets cannot have two items with the same value.

example

x = {"apple", "banana", "cherry", "apple"}

print(x) # Duplicate values will be ignored:

x = {"apple", "banana", "cherry", True, 1, 2}

print(x)

print(len(x))

print(type(x))

Python Dictionaries

Dictionaries are used to store data values in key:value pairs.

A dictionary is a collection which is ordered*, changeable and do not allow duplicates.

Dictionaries are written with curly brackets, and have keys and values.

example:

a = {'key_1':[1,2,3],

'key_2':(11,22,33),

'key_4':{111,333,222},

'key_5':'value_0',

'key_6':{'key_1':[10,20,30],

'key_2':(100,200,300),

'key_4':{1000,2000,3000},

'key_5':'value_5'}}

print(a)

print(len(a))

print(type(a))

Changeable

Dictionaries are changeable, meaning that we can change, add or remove items after the dictionary has been created.

Duplicates Not Allowed

Dictionaries cannot have two items with the same key:

Python Conditions and If statements

In Python, condition statements act depending on whether a given condition is true or false. You can execute different blocks of codes depending on the outcome of a condition. Condition statements always evaluate to either True or False.

There are three types of conditional statements.

if statement
if-else
if-elif-else
nested if-else

If - else -elif-nested if statement in Python

In control statements, the if statement is the simplest form. It takes a condition and evaluates to either true or false

Example: if statement a = 33

b = 200

if b > a:

print("b is greater than a")

Example: if-elif

                           a = 33
                           b = 33
                           if b > a:
                             print("b is greater than a")
                           elif a == b:
                             print("a and b are equal")

If the condition is true, the True block of code will be executed, and if the condition is False, then the block of code is skipped, and The controller moves to the next line

Example: if-elif-else

                       a = 200
                       b = 33
                       if b > a:
                         print("b is greater than a")
                       elif a == b:
                         print("a and b are equal")
                       else:

print("a is greater than b")

Example:

Q1) Write a Python program that takes an integer as input from the user and checks if the number is positive, negative, or zero.